The CDC collects biometric data on the US population. Two weight measurements (12 months apart) are taken on a sample of 25 US citizens. The average difference of weights in the sample is 0 lbs and its standard deviation is 5 lbs. A confidence interval is calculated as (-1.96, 1.96). What is the correct interpretation for this confidence interval?
a. We are 95% confident that the population average difference in the two independent groups is between -1.96 and 1.96.
b. We are 95% confident that the population average difference in the two dependent groups is between -1.96 and 1.96.
c. We are 95% certain that the sample average difference in the two dependent groups is between -1.96 and 1.96.
d. There is a 95% chance that the sample average difference between the two dependent groups is between -1.96 and 1.96.